Direct Angioplasty for Acute Occlusion of Intracranial Artery

We have read with interest the article Direct Percutaneous Transluminal Angioplasty for Acute Middle Cerebral Artery Occlusion by Nakano and colleagues (1). The authors report their experience using direct percutaneous angioplasty (PTA) as the sole means of treating 10 patients with acute middle cerebral artery (MCA) occlusion when the initial CT scans demonstrate early ischemic changes or involvement of lenticulostriate arteries or both. The authors’ rationale for choosing direct PTA alone to establish blood flow without using thrombolysis is based on the high risk of hemorrhagic complications in this group of patients. The authors believe that avoiding thrombolytic therapy can reduce such a risk. The angiographic success rate in their patients was relatively high (80%), and there were no hemorrhagic complications; however, only two patients had full recovery. With 20% clinical recovery and 20% distal embolization, the rationale for their method becomes debatable despite a high rate of angiographic success without hemorrhagic complications.

We wonder whether the authors may have overlooked the fundamental pathophysiology that causes hemorrhagic complications during acute ischemic stroke. Patients with early ischemic findings on initial CT scans have a high risk of hemorrhage after re-established blood flow primarily because of the high incidence of reperfusion of irreversibly damaged ischemic tissue. The thrombolytic agent can contribute to but is not the primary cause of hemorrhagic complications (ie, reperfusion of dead tissue). The most effective way to prevent such complications is either to avoid reperfusion of irreversibly damaged tissue or to recanalize the occluded vessel as early as possible. In some patients, the blood flow of the cortex in the distal MCA territory can be rescued by recanalization of the occluded M1 segment by using direct angioplasty. Angioplasty alone, however, will not dissolve the clot nor re-establish the blood flow effectively, particularly in the perforators, but will further propagate the clot distally. Therefore, the relatively low rates of hemorrhage and clinical recovery suggest that their technique of performing angioplasty alone may not be as effective in re-establishing the blood flow. If the authors believe that early ischemic findings on the initial CT scan suggest irreversibly damaged tissue and a high risk of hemorrhage, then early interventional treatment, including PTA, should not be performed in patients who have such findings.

One important question in the treatment of acute stroke is whether we are treating reversible ischemia. Our previous reports suggest that reversibility of ischemic tissue can be assessed by single-photon-emission CT of pretreatment CBF, which can help in the selection of appropriate patients for thrombolysis by reducing hemorrhagic complications and improving outcome (2, 3). Our previous experience also suggests that a combination of thrombolysis and angioplasty is effective in failed thrombolysis cases or reocclusion cases (4). We strongly believe that angioplasty is an effective option in reperfusion therapy for acute ischemic stroke and can shorten the duration of ischemia and improve the success rate of recanalization. Most importantly, the purpose of angioplasty should be to improve the neurologic systems of stroke patients by increasing CBF, not to improve angiographic results.